Question: The S.I. unit of gravitational potential is: [PMT/NEET-2000]
a. J
b. J–kg$^{-1}$
c. J–kg
d. J–kg$^{-2}$

Answer: b. J–kg$^{-1}$

Solution: Gravitational potential $V=W/m$. Since $W$ in joule and $m$ in kilogram, $[V]=\text{J kg}^{-1}$. For example $V=-GM/r$ has dimensions $L^{2}T^{-2}$.